JPS631503B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a hot water supply control device for a hot water storage type water heater,
The details relate to measures to prevent dry running of hot water pumps that supply hot water from a hot water storage tank. Conventionally, this type of hot water supply control device includes a hot water pump that pumps hot water from a hot water storage tank heated by a heating device to the tank via a hot water supply passage, and a hot water supply pump that turns on when the amount of stored hot water flowing through the hot water supply passage exceeds a predetermined amount. A flow switch that operates, a pressure switch that operates when the pressure in the hot water supply passage is below a predetermined pressure, and a control circuit that operates the hot water pump in response to an ON activation signal from at least one of the flow switch and the pressure switch. It is known that the control circuit controls the operation of a hot water pump to forcefully feed hot water in a hot water storage tank to a tank. However, in the conventional system described above, when the water supply to the hot water tank stops when the hot water pump is operating, or when the amount of water added to the hot water tank becomes less than the amount of hot water stored from the hot water tank to the tank, the hot water supply passage Water was no longer supplied to the area, but the hot water pumps continued to operate. In other words, the flow switch turns OFF as the amount of hot water decreases, but the pressure in the hot water passage is below the predetermined pressure, the same as when the tap is open and hot water is being supplied, so the pressure switch is turned ON.
The hot water pump is operating, and the control circuit continues the operation of the hot water pump, causing the hot water pump to run dry. As a result, noise is generated by the air mixed into the hot water, and because the hot water pump is lubricated by the hot water it sucks, it may burn out due to insufficient cooling and lubrication due to a decrease in the amount of hot water supplied or the stoppage of hot water supply. There was a drawback that there was. In view of this, the first invention of the present application is designed to ensure that the operating states of the flow switch and the pressure switch in the dry running state of the hot water pump as described above are as shown in the table below, except during the transition period when the switch is open. Focusing on the fact that it is different from the normal operating state (including the stopped state), both the OFF operating state of the flow switch and the ON operating state of the pressure switch continue for a longer time than the set time corresponding to the transition period when the switch is opened. In this case, it is determined that the replenishment water has stopped or is insufficient, and the operation of the hot water pump is forcibly stopped. This eliminates noise caused by air intrusion without impairing the original hot water supply function. The purpose of this is to prevent hot water pumps from burning out.

[Table] In order to achieve this object, the first invention of the present application includes a hot water supply pump that pumps hot water from a hot water storage tank heated by a heating device to the tank through a hot water supply passage;
When the amount of hot water flowing through the hot water supply passage is more than a predetermined amount
A flow switch that operates ON, a pressure switch that operates ON when the pressure in the hot water supply passage is below a predetermined pressure, and a control circuit that operates the hot water pump in response to an ON activation signal from at least one of the flow switch and the pressure switch. In the hot water supply control device of the hot water storage type water heater, the flow switch OFF operation signal and the pressure switch ON
The flow switch is equipped with a timer that receives an activation signal and outputs a protection signal when the reception state continues for a predetermined period of time, and a first protection device that stops the operation of the hot water pump upon receiving the protection signal of the timer.
When both the OFF operating state and the ON operating state of the pressure switch continue for a predetermined period of time, a protection signal from the timer activates the protection device and forcibly stops the operation of the hot water pump. In addition, the second invention of the present application provides a method for idling the hot water pump in view of the fact that it is not desirable for safety to operate the heating device that heats the hot water in the hot water storage tank when the hot water pump is in the dry running state as described above. The purpose of this is to forcibly stop the operation of the heating device as well as the hot water pump when the condition occurs, thereby sufficiently ensuring the safety of the device. Therefore, in addition to the configuration of the first invention, the configuration of the second invention of the present application is to provide a timer protection signal separately from the first protection device that stops the operation of the hot water pump in response to the timer protection signal. A second protection device is provided to stop the operation of the heating device in response to the above-mentioned water supply pump, and when the hot water pump is running dry, the protection signal of the timer causes the hot water pump to be forcibly stopped and the second protection device is also activated to stop the heating device. It is designed to forcibly stop the operation. Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a hot water supply control device for a heat pump type water heater, in which 1 is a hot water storage tank, 2 is a water heat exchanger immersed in the water stored in the hot water storage tank 1, and The water heat exchanger 2 is connected to a compressor 4, an expansion valve 5, and an evaporator 6 through refrigerant piping 3 so that the refrigerant can circulate, and evaporates by circulating the refrigerant in the direction shown by the solid arrow in the figure. vessel 6
A heating device 7 is configured to supply the heat obtained in the above to the water heat exchanger 2 to heat the water stored in the hot water storage tank 1. Reference numeral 8 denotes a hot water supply pump that communicates with the hot water of the hot water storage tank 1 via a suction passage 9. A collar 11 is connected to the hot water supply pump 8 via a hot water supply passage 10. As a result of this operation, hot water in the hot water storage tank 1 is force-fed from the suction passage 9 through the hot water supply passage 10 to the hot water tank 11. Further, in the middle of the hot water supply passage 10, a flow switch 12 which is turned on when the amount of hot water flowing through the hot water supply passage 10 exceeds a predetermined amount, and an accumulator 13 are provided.
A pressure switch 14 is provided which is turned on when the pressure of the pressure is below a predetermined pressure. The control circuit 25 also includes the heating device 7.
The excitation circuit 27 of the operation control relay MR 4 is equipped with an operation control relay MR ₄ that controls the ON/OFF operation of the compressor ₄ , which is a drive device for the hot water storage tank 1. A hot water temperature thermostat 22 is provided which closes when the temperature is below a set value, and when the hot water temperature in the hot water storage tank 1 is below the set value, the excitation circuit 27 is closed by closing the hot water temperature thermostat 22. By turning on the operation control relay MR ₄ , the compressor 4 is turned on and the heating device 7 is activated to raise the hot water temperature. However, when the hot water temperature exceeds the set value, the hot water temperature thermostat is turned on. 22 opens the excitation circuit 27 and turns off the operation control relay MR ₄ , thereby turning off the compressor 4.
It is configured to stop the operation of the heating device 7 and stop the operation of the heating device 7. Next, a control circuit for controlling the operation of the hot water pump 8 is shown in FIG. The control circuit 25 is turned on and off in response to the ON and OFF operation of the pressure switch 14.
A reaction relay MR ₁ that turns OFF and a reaction relay MR ₂ that turns ON and OFF in accordance with the ON and OFF operation _of the flow switch 12 are provided. _Two normally open contacts MR ₁ - ₁ and MR ₂ - ₁ are provided in parallel, and when at least one of the pressure switch 14 and flow switch 12 is turned on, the corresponding reaction relays MR ₁ and MR ₂ are turned on. normally open contact
The hot water supply pump 8 is configured to be operated by generating an ON operation signal by closing MR ₁ - ₁ and MR ₂ - ₁ and closing the power supply circuit 26. The control circuit 25 includes a timer TM, which is important in the configuration of the present invention, and a normally open contact of the timer TM.
A relay MR ₃ is provided which is turned on when TM ₁ is closed. The timer TM receives an ON operation signal generated when the other normally open contact MR ₁ - ₂ of the reaction relay MR ₁ of the pressure switch 14 is closed, and a normally closed contact MR ₂ - of the reaction relay MR ₂ of the flow switch 12. ₂
When this receiving state continues for a predetermined time T (for example, 30 seconds) which is longer than the transition period (usually several seconds) when the contact 11 is closed, the normally open contact TM ₁ When closed, a protection signal is output and relay MR ₃ is turned ON. Then, the power supply circuit 26 of the hot water pump 8
and a compressor 4 which is a driving device for the heating device 7.
In the excitation circuit 27 of the operation control relay MR ₄ ,
Normally closed contacts MR ₃ - ₁ and MR ₃ - ₂ of the above relay MR ₃ are provided, respectively, so that the above timer
When relay MR ₃ receives the TM protection signal and turns on, its normally closed contacts MR ₃ - ₁ and MR ₃ - ₂ are opened.
A first protection device 28 configured to stop the operation of the hot water pump 8, and the operation control relay described above.
A second protection device 29 is configured to stop the operation of the compressor 4 and the heating device 7 when the MR ₄ is turned off. Note that 22 in FIG. 2 is a hot water temperature thermostat that closes when the hot water temperature in the hot water storage tank 1 is below a set temperature. Reference numeral 15 in FIG. 1 is a ball tap valve which allows water to be supplied from the water replenishment pipe 16 when the water level in the hot water storage tank 1 falls below a predetermined value. This controls the water replenishment into the tank via the tank. In addition, 18 is hot water supply passage 1
0 is a check valve, 19 is a solenoid valve for preventing freezing of pipes in the machine, 20 is a hot water discharge valve, and 21 is an overflow pipe. Next, to explain the operation of the above embodiment,
In a normal state where the amount of water refilled into the hot water storage tank 1 is an appropriate amount, when the hot water supply passage 10 is initially opened, that is, during a transitional period when the amount of hot water flowing through the hot water supply passage 10 is less than a predetermined amount (usually for several seconds), the hot water supply passage 10 The water supply pump 8 starts operating by turning on the pressure switch 14 due to the pressure drop within the tank and thereby closing the normally open contact MR ₁ - ₁ of the reaction relay MR ₁ . At this time, the timer TM is turned on by closing the normally open contact MR ₁ - ₂ of the reaction relay MR ₁ of the pressure switch 14.
Actuation signal and flow switch 12 reaction relay
The OFF operation signal is received by the closing of the normally closed contact MR ₂ - ₂ of MR ₂ , but since the duration of this reception state is within the predetermined time T (for example, 30 seconds), the timer
No protection signal is output from the TM, and the operation of the hot water pump 8 is not forcibly stopped. When the amount of hot water flowing through the hot water supply passage 10 exceeds a predetermined amount and enters a stable state, the flow switch 12 is turned on and the normally open contact of the reaction relay MR _{2 is} turned on _.
By closing, the operation of the hot water pump 8 continues. Now, in this state, water replenishment to hot water tank 1 has stopped,
Or, if the amount of replenishing water becomes less than the amount of hot water supplied from the hot water storage tank 1, air will enter the hot water supply passage 10 at some point due to the decrease in the amount of hot water in the hot water storage tank 1, or hot water will no longer flow at all. . At this time, the flow switch 12 turns OFF as the amount of hot water supply decreases, but the pressure switch 14 continues to turn ON because the pressure in the hot water supply passage 10 remains low, and the hot water pump 8 turns OFF. Operation continues by closing the normally open contact MR ₁ - ₁ of reaction relay MR ₁ of No. 14, resulting in a dry running state. However, when the pressure switch 14 is turned ON, the normally open contact MR ₁ - ₂ of the reaction relay MR ₁ is closed, and when the flow switch 12 is turned OFF, the reaction relay is closed.
When the normally closed contact MR _{2 of MR 2 continues} to be closed for a predetermined time T, the normally open contact TM ₁ of the timer TM
is closed and a protection signal is output. For this reason, relay MR ₃ is activated, its normally closed contacts MR ₃ - ₁ and MR ₃ - ₂ are opened, and the operation of hot water pump 8 and the ON activation of compressor relay MR ₄ are forcibly stopped. That will happen. As a result, the hot water supply pump 8 is prevented from running idly, and the generation of noise and burnout of the hot water supply pump 8 due to air mixing into the hot water supply passage 10 are prevented. Also, at the same time,
Since the operation of the heating device 7 is forcibly stopped, safety is ensured by protecting the heating device 7. In the above embodiment, when the water supply to the hot water tank 1 is stopped or there is insufficient water, the operation of the hot water supply pump 8 and the operation of the heating device 7 are forcibly stopped, but in addition to this, the buzzer may be sounded. It is more preferable to call attention to taking safety measures such as turning on a warning lamp or stopping hot water supply. Further, in the above embodiment, a case has been described in which the application is applied to a hot water supply control device of a heat pump water heater, but the present invention is not limited to this, and the present invention may also be applied to a method in which solar heat is collected to heat hot water in a hot water storage tank. Of course, the present invention can also be similarly applied to a hot water supply control device for a hot water storage type water heater. As explained above, according to the first invention of the present application, when at least one of the flow switch and the pressure switch is turned ON, the hot water supply pump is operated by the control circuit, and the hot water in the hot water tank heated by the heating device is heated. In a hot water supply control device for a hot water storage type water heater that is configured to forcefully send water to a hot water tank, when the flow switch is turned OFF and the pressure switch is turned ON for a predetermined period of time, the first protection device is activated by a protection signal from the timer. I activated it to forcibly stop the operation of the hot water pump, so
This makes it possible to reliably prevent noise generation and burnout of the hot water pump due to dry running of the hot water pump. In addition, in the second invention of the present application, the hot water pump is forcibly stopped by the protection signal from the timer, and the second protection device is activated to forcibly stop the operation of the heating device. The heating device can be protected when water replenishment is stopped or insufficient, and safety can be improved in addition to the effects of the first invention.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a water supply piping system diagram of a hot water storage tank, and FIG. 2 is an electric circuit diagram of a hot water supply control device. 1... Hot water storage tank, 7... Heating device, 8... Hot water pump,
10...Water supply passage, 11...Turn, 12...Flow switch, 14...Pressure switch, 25...Control circuit,
28...First protective device, 29...Second protective device, TM
...Timer.

Claims (1)

[Scope of Claims] 1. A hot water pump 8 that pumps hot water from a hot water storage tank 1 heated by a heating device 7 to a hot water tank 11 through a hot water supply passage 10, and when the amount of hot water flowing through the hot water supply passage 10 is equal to or greater than a predetermined amount. Flow switch 1 that turns ON
2, a pressure switch 14 that is turned ON when the pressure of the hot water supply passage 10 is below a predetermined pressure, and a pressure switch 14 that is turned ON by an ON operation signal of at least one of the flow switch 12 and the pressure switch 14.
In the hot water supply control device for the hot water storage type water heater, which is equipped with a control circuit 25 for operating the flow switch 12 and the pressure switch 1,
a timer TM that receives the ON activation signal of 4 and outputs a protection signal when this reception state continues for a predetermined time;
A hot water supply control device for a hot water storage type water heater, comprising a first protection device 28 that stops the operation of the hot water pump 8 in response to a protection signal from the timer TM. 2. A hot water pump 8 that pumps the hot water in the hot water storage tank 1 heated by the heating device 7 to the hot water tank 11 through the hot water supply passage 10, and a flow switch that is turned on when the amount of hot water flowing through the hot water supply passage 10 is equal to or higher than a predetermined amount. 1
2, a pressure switch 14 that is turned on when the pressure in the hot water supply passage 10 is below a predetermined pressure, and a control circuit 25 that operates the hot water pump 8 in response to an ON signal from at least one of the flow switch 12 and the pressure switch 14. In the hot water supply control device for a hot water storage type water heater, the flow switch 12
OFF operation signal and the pressure switch 14
a timer TM that receives an ON operation signal and outputs a protection signal when this reception state continues for a predetermined time; a first protection device 28 that stops the operation of the hot water pump 8 upon receiving the protection signal of the timer TM; A hot water supply control device for a hot water storage type water heater, comprising a second protection device 29 that stops the operation of the heating device 7 in response to a TM protection signal.